Size=n and optgroup break select boxes in IOS6 webkit browsers (crash)

As of IOS6, webkit browsers (safari,chrome) will crash when you select a value on a select box that contain a size attribute and optgroup elements.

To reproduce this bug, have an html page with the following html (and select an option from the box):

<select size="2"> <optgroup> <option>Crash Me</option> </optgroup> </select>